Feeling Low...

Since about noon I have felt "off", almost like my blood sugar is too low...but I've been checking it and its been between 5.9 and 8.0 all day (for non diabetic speakers, that is just about PERFECT). I feel cranky, tired, listless, anxious, not focused, light headed. I had an apple around 2 p.m.but that didn't seem to help, so I'm not hungry. I drank lots of water so I'm not dehydrated, I don't think. 

I drove home from work with all the windows rolled down and the radio blaring to try and keep me alert, but I still feel like I drove home on auto-pilot, you know? I don't feel "sleepy" tired, just worn out and it came on all of a sudden almost right after lunch - which was not high in carbs either.

I'm going to try and have a short nap before I start dinner and see if that helps.  More later.